code: def test_qubit_observable_cutoff(f_observable, cut_off):
      """Test that qubit_observable returns the correct operator when a cutoff is provided."""
      h_ref, h_ref_op = (
          qml.Hamiltonian([], []),
          qml.s_prod(0, qml.Identity(0)),
      )
      h_as_hamiltonian = qchem.qubit_observable(
          f_observable, cutoff=cut_off
      )
  
      enable_new_opmath()
      h_as_op = qchem.qubit_observable(f_observable, cutoff=cut_off)
      disable_new_opmath()
  
      assert h_as_hamiltonian.compare(h_ref)
      assert qml.equal(h_as_op, h_ref_op)
      assert np.allclose(
          qml.matrix(h_as_op, wire_order=[0, 1, 2]),
          qml.matrix(h_ref_op, wire_order=[0, 1, 2]),
      )
  
file_path: pennylane/tests/qchem/test_observable_hf.py
imports: import pytest
  import pennylane
  from pennylane import numpy
  from pennylane import qchem
  from pennylane.pauli import pauli_sentence
  from pennylane.operation import enable_new_opmath, disable_new_opmath
  from pennylane.fermi import from_string
label_desc: Use image node_id 3 for calling a global function with example usage: test_qubit_observable_cutoff(f_observable, cut_off) without return types